DESCRIPTION: There is recent evidence to suggest that ELF-MF may function as a tumor promoter, and as a co-mutagen with radiation and chemical carcinogens. Preliminary studies by the applicant have shown a 2-3 fold enhancement in the mutagenicity of the direct alkylating agent MNNG, by magnetic fields. The present project proposes to extend these findings by examining the combined mutagenic effects of ELF-MF with either gamma-rays or benzopyrene, at both the cellular and molecular levels. Mutation will be scored at both the S1 and HGPRT loci using the human-hamster hybrid AL cells. Quantitative mutagenesis data will be used in assessing the mode of interaction between ELF-MF and the other two known human carcinogens. Molecular spectra will be used to ascertain the presence or absence of specific signature changes at the gene level. The molecular basis for mutations in the AL cells will be examined, both by using specific DNA probes of other genes that have been regionally mapped to various sites on chromosome 11, and by Southern blot analysis of hprt mutants.